A tuning credit should be added for vocaloid releases as the current credits on MBz don't really encompass the role.

Essentially, tuning is an extra step in the process of making vocaloid music where the artist tunes the voice to notes (correct me if I'm wrong here). In that sense, this could also cover auto-tuning for human vocals.

'Programming' a vocal synthesizer doesn't properly cover the role as often times this task is split into multiple components between artists. (Ex. https://www.youtube.com/watch?v=fTz4phIeBls)

https://community.metabrainz.org/t/how-should-i-credit-an-artist-for-tuning-a-vocal-synth/778601